1. Field of the Invention
The present invention relates to an image processing apparatus and method thereof and, more particularly, to an image process that realizes preferred color reproduction at high speed.
2. Background of the Invention
An image processing apparatus which makes color correction often uses 3×3 matrix operations and gamma conversion so as to attain a high-speed color process and a reduction of the circuit scale. Such matrix operations and gamma conversion can achieve arithmetically faithful color conversion, but cannot achieve preferred color reproduction in correspondence with one's memory colors and favor.
In order to convert color-corrected data into a CMYK signal depending on an output device, the color corrected data undergoes luminance-density conversion, and then undergoes a masking process, under color removal process, and black correction process. These processes impose heavy loads, and it is difficult to attain a size reduction of that circuit.
As a method that can compensate for the above drawbacks, a color difference diffusion (CD) method disclosed in Japanese Patent Laid-Open No. 11-55535 is known. With this method, the distances on a color space are calculated for respective combinations of colors that an output device can reproduce, so as to associate colors closest to those of input image data with each other, and a combination of colors that can minimize the distances is selected. Furthermore, this method is a technique which can implement an arrangement for diffusing the differences among associated colors to other pixels by a small-scale circuit, and can improve a high-speed process and color reproducibility.
However, even when the CD method which allows high-speed color separation is used, it is difficult to attain preferred color reproduction corresponding to various user's requirements using a small-scale circuit.